The worldwide use of antibiotics for the treatment of infectious diseases has drastically increased over the last 40 years. Two million pounds of antibiotics were produced only in the United States in 1954, and the current production thereof amounts to over 50 million pounds, from which the extent of increase in the use of antibiotics may be estimated. Furthermore, in accordance with the Center for Disease Control and Prevention (CDC), 235 million doses of antibiotics are consumed by people yearly.
Doripenem is a carbapenem antibiotic that is active against a wide variety of gram-negative bacteria and gram-positive bacteria, and it has the chemical name of ((4R,6S)-6-((R)-1-hydroxyethyl)-4-methyl-7-oxo-3-(((3S,5S)-5-((sulfamoylamino)-methyl)pyrrolidin-3-yl)thio)-1-azabicyclo[3.2.0]hep-2-ene-2-carboxylic acid, and is represented by Chemical Formula 1 below.

Although doripenem is known for taking the form of Type 1 to V hydrate crystals, a Type IV doripenem hydrate crystal, currently commercially available, has low solubility and thus its suspension has to be diluted before use, which is undesirable.
In addition, a recrystallization process is performed to increase the quality of doripenem during the preparation thereof. As such, water is used as a solvent for dissolving doripenem. Taking into consideration the yield, a small amount of water is used, and adjusting the pH or increasing the temperature may be conducted to completely dissolve doripenem, but is problematic because the purity of doripenem may be decreased.
Meanwhile, Korean Patent No. 10-0472848 discloses a method of preparing Type III and Type IV doripenem hydrates, and Korean Patent No. 10-0314558 discloses Type I and Type II doripenem hydrates, in which the need to increase stability is described, but problems related to the increase in solubility of doripenem or the simplification of the preparation method thereof still occur.
Hence, it is required to provide doripenem that is simply prepared and has high solubility and stability.